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Revision as of 02:44, 27 February 2010

Aconitase

Aconitase (PDB 2b3x) catalyzes the reversible isomerization of citrate and isocitrate.

Mechanism of Aconitase

Template:STRUCTURE 2b3x

Stage 1: Dehydration

First, dehydration of citrate causes a proton and OH group to be removed from only the 'lower arm'.^[1] This forms a cis-Aconitate intermediate.

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Aconitase contains . This iron sulfur cluster does not participate in redox as most do, but coordinates the OH goup of citrate to facilitate its elimination.^[2]

Stage 2: Rehydration

The second main stage of the reaction is the rehydration of the cis-Aconitate intermediate. This forms isocitrate. It is catalyzed in a stereospecific way such that only one isocitrate stereoisomer is formed. ^[3]

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Thus, the overall reaction that aconitase catalyzes is:

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References

1. ↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 578. Print.
2. ↑ Dupuy J, Volbeda A, Carpentier P, Darnault C, Moulis JM, Fontecilla-Camps JC. Crystal structure of human iron regulatory protein 1 as cytosolic aconitase. Structure. 2006 Jan;14(1):129-39. PMID:16407072 doi:10.1016/j.str.2005.09.009
3. ↑ Voet, Donald, Judith G. Voet, and Charlotte W. Pratt. Fundamentals of Biochemistry Life at the Molecular Level. New York: John Wiley & Sons, 2008. p. 579. Print.

External Links

Aconitase on Wikipedia

Aconitase on Proteopedia

(http://www.ncbi.nlm.nih.gov/pmc/articles/PMC287193/ More PubMed)